Graphite is:
a. harder than glass.
b. the lead in the pencil you write with.
c. the polymorph of galena.
d. composed of carbon atoms, arranged as tetrahedrons, held together with strong covalent bonds.
e.
You listed a fifth answer, but didn't actually provide it, just so you know, but no matter, the answer you're looking for is D. Composed of carbon atoms, arranged as tetrahedrons, held together with strong covalent bonds.